In fluid flow machines, particularly in gas turbines, such as aircraft engines, there are a number of application cases which require sealing two parts which move relative to each other, namely a stator and a rotor of the fluid flow machine, from a gas flow streaming through the fluid flow machine. Gas turbines, in particular, have, inter alia, at least one compressor, as well as at least one turbine, the or each compressor, as well as the or each turbine having a rotor which rotates relative to a fixed stator. The stator is, in particular, a stationary housing having associated fixed guide vanes. The rotor of a turbine or of a compressor has associated rotor blades, which rotate together with the rotor relative to the fixed guide vanes, as well as relative to the stationary housing.
To optimize the efficiency of gas turbines, in particular, it is necessary, inter alia, to minimize leakage flows between the rotating rotor and the fixed stator of the compressor and turbine. This requires, in particular, sealing a gap between the radially inside ends of the fixed guide vanes and the rotating rotor. A sealing arrangement for sealing the gap between the radially inside ends of the fixed guide vanes and the rotating rotor is also described as an “inner air seal.” Another gap to be sealed is located, for example, between the radially outside ends of the rotating rotor blades and the stationary housing. A sealing arrangement for sealing the gap between the radially outside ends of the rotating rotor blades and the housing is also described as an “outer air seal.”
In addition, there are other gaps to seal between a rotating rotor and a fixed stator. Sealing arrangements between a rotor and a stator are also referred to as dynamic sealing arrangements.
From the related art, it is already known to design dynamic sealing arrangements as brush seals, in order to non-hermetically seal a gap between a rotor and a stator. Reference is made here to related-art brush seals, as described in German Patents DE 195 27 605 C2 or DE 101 22 732 C2. In the case of the above-mentioned brush seals known from the related art, the brush seal is made of a plurality of wire-type bristles which are wound around a bristle carrier, the bristle carrier being constituted of a core element and of a clamping ring. The unit made up of a bristle carrier and bristles, which forms the actual brush seal, is arranged in a receiving space defined by a support ring and a cover ring.
In the brush seals in accordance with German Patents DE 195 27 605 C2 and DE 101 22 732 C2, the bristle carrier, made up of the core element and of the clamping ring, is designed as a closed ring, which is fixedly or immovably positioned, in particular clamped in the receiving space. This design of the bristle carrier as a closed ring, as known from the related art, results in a substantially inelastic bristle carrier, so that it is only possible to partially compensate, on the one hand, for example, for eccentricities of or other mechanical variations in the gap to be sealed between the rotor and the stator and, on the other hand, for thermal variations, caused, for example, by different thermal expansion coefficients, in the gap to be sealed between the rotor and stator of known brush seals. In related-art brush seals, a dynamically changing gap to be sealed is compensated exclusively by deflection of the bristles, resulting, on the one hand, in the generation of considerable frictional heat, and, on the other hand, in substantial wear to the bristles of the brush seal. Accordingly, the brush seals known from the related art are only able to compensate less than adequately for variations in the gap to be sealed that occur during operation.